1. Field of the Invention
The present invention relates to an apparatus for assembling a pair of fastener elements of a garment fastener, such as a snap fastener, a button or an ornament, with a garment fabric disposed between the two fastener elements.
2. Prior Art
Various fastener-assembling apparatus are known in which a pair of fastener elements of a garment fastener is supported on a lower or die unit and an upper or punch unit, respectively; a punch of the upper unit moves toward a die of the lower unit to join the two fastener elements together in clinched condition, with a garment fabric sandwiched between the two fastener elements. In most of the known apparatus, a drive mechanism for moving the punch vertically includes an air cylinder having a reciprocable piston rod, and a toggle joint for transferring reciprocating motion from the piston rod to the punch. As the piston rod reciprocates, the toggle joint is movable between a contracted position in which two levers are angled to each other, and an extended position in which the two levers are verticaly aligned. A common problem with the apparatus of this type is that if there is play in joints between the piston rod, the levers and the punch, or if there is any flash or fin on the punch or on an associated part along which the punch reciprocates, the toggle joint cannot be fully extended to a required extent even though the amount of extension of the piston rod is adjusted or set precisely. As a consequence, the punch would often fail to reach a predetermined lower level in which the button and the tack are to be sufficiently compressed between the punch and the die.